Myers’ PSYCHOLOGY (5th Ed) Chapter 11 Intelligence James A. McCubbin, PhD Clemson University Worth Publishers

Origins of Intelligence zIntelligence Test ya method of assessing an individual’s mental aptitudes and comparing them to those of others, using numerical scores

Origins of Intelligence zMental Age ya measure of intelligence test performance devised by Binet ychronological age that most typically corresponds to a given level of performance ychild who does as well as the average 8-year-old is said to have a mental age of 8

Origins of Intelligence zStanford-Binet ythe widely used American revision of Binet’s original intelligence test xrevised by Terman at Stanford University

Origins of Intelligence zIntelligence Quotient (IQ) ydefined originally the ratio of mental age (ma) to chronological age (ca) multiplied by 100 xIQ = ma/ca x 100) yon contemporary tests it is the average performance for a given age is assigned a score of 100

What is Intelligence? zIntelligence ycapacity for goal-directed and adaptive behavior yinvolves certain abilities xprofit from experience xsolve problems xreason effectively

What is Intelligence? zIQ is a score on a test yit is not something you have zIs intelligence singular or multiple abilities? zDoes it relate to speed of brain processing?

Intelligence zIs intelligence culturally defined? zAre intelligence tests culture free?

Is Intelligence Neurologically Measurable? zBrain size correlation to intelligence: +.33 yWhat does this mean? zPortion sizes vary as well yEinstein had abnormally large parietal lobes zEnvironmental experiences impact yRat neural connections example yHighly educated people die with 17% more synapses than counterparts

Other Environmental Influences zInfants who suffer from extreme malnutrition during infancy average 20 I.Q. points lower than other children (Stock and Smythe, 1963) zToxins in the environment such as lead found in some paints are associated with reduced I.Q. (Needleman, 1990) zIntelligence declines with family size; the fewer children there are the smarter you are likely to be (Zajonc, 1975) zIntelligence declines with birth order; first-borns tend to be brighter (Zajonc, 1975) zI.Q. is negatively correlated with family risk factors, such as social class or absence of father figure (1989)

Are There Multiple Intelligences? zFactor Analysis ystatistical procedure that identifies clusters of related items (called factors) on a test yused to identify different dimensions of performance that underlie one’s total score zGeneral Intelligence (g) yfactor that Spearman and others believed underlies specific mental abilities ymeasured by every task on an intelligence test

Are There Multiple Intelligences? zSavant Syndrome ycondition in which a person otherwise limited in mental ability has an amazing specific skill xcomputation xdrawing

Are There Multiple Intelligences? zSocial Intelligence ythe know-how involved in comprehending social situations and managing oneself successfully zEmotional Intelligence zability to perceive, express, understand, and regulate emotions zcritical part of social intelligence

Brain Function and Intelligence zPeople who can perceive the stimulus very quickly tend to score somewhat higher on intelligence tests Stimulus Mask Question: Long side on left or right?

Assessing Intelligence zAptitude Test ya test designed to predict a person’s future performance yaptitude is the capacity to learn zAchievement Test ya test designed to assess what a person has learned

Assessing Intelligence zWechsler Adult Intelligence Scale (WAIS) ymost widely used intelligence test ysubtests xverbal xperformance (nonverbal) zWechsler Intelligence Scale for Children (WISC) ysimilar to WAIS, but for school children

Assessing Intelligence- Sample Items from the WAIS From Thorndike and Hagen, 1977 VERBAL General Information Similarities Arithmetic Reasoning Vocabulary Comprehension Digit Span PERFORMANCE Picture Completion Picture Arrangement Block Design Object Assembly Digit-Symbol Substitution

Assessing Intelligence zStandardization ydefining meaningful scores by comparison with the performance of a pretested “standardization group” zNormal Curve ythe symmetrical bell-shaped curve that describes the distribution of many physical and psychological attributes ymost scores fall near the average, and fewer and fewer scores lie near the extremes

The Normal Curve Ninety-five percent of all people fall within 30 points of 100 Number of scores Wechsler intelligence score Sixty-eight percent of people score within 15 points above or below 100

Getting Smarter? Flynn Effect: IQ scores going up about 3 points per decade

Assessing Intelligence zReliability ythe extent to which a test yields consistent results yassessed by consistency of scores on: xtwo halves of the test xalternate forms of the test xretesting the same individual zValidity ythe extent to which a test measures or predicts what it is suppose to

Assessing Intelligence zContent Validity ythe extent to which a test samples the behavior that is of interest xdriving test that samples driving tasks zCriterion ybehavior (such as college grades) that a test (such as the SAT) is designed to predict ythe measure used in defining whether the test has predictive validity

Assessing Intelligence zPredictive Validity ysuccess with which a test predicts the behavior it is designed to predict yassessed by computing the correlation between test scores and the criterion behavior yalso called criterion-related validity

Assessing Intelligence zAs the range of data under consideration narrows, its predictive power diminishes. zTherefore, the predictive power of aptitude tests scores diminish as students move up the educational ladder. Greater correlation over broad range of body weights Little corre- lation within restricted range Football linemen’s success Body weight in pounds

The Dynamics of Intelligence  Is intelligence stable across the lifespan or does it change? Intelligence test scores don’t stabilize until about age 7; after that about a +.66 correlation over time

The Dynamics of Intelligence zMental Retardation ya condition of limited mental ability yindicated by intelligence scores below 70 yproduces difficulty in adapting to the demands of life yvaries from mild to profound

The Dynamics of Intelligence zDown syndrome yretardation and associated physical disorders caused by an extra chromosome in genetic make-up

The Dynamics of Intelligence Degrees of Mental Retardation Level Typical Intelligence Scores Percentage of the Retarded Adaptation to Demands of Life Mild % May learn academic skills up to sixth-grade level. Adults may, with assistance, achieve self-supporting social and vocational skills. Moderate May progress to second-grade level. academically. Adults may contribute to their own support by labor in sheltered workshops. Severe May learn to talk and perform simple work tasks under close supervision but are generally unable to profit from vocational training. Profound Below Require constant aid and supervision.

Tracking zFrom early age students are often tracked into “gifted” programs and “remedial” programs… what’s a potential problem with this? ySelf-Fulfilling Prophecy

The Dynamics of Intelligence zCreativity ythe ability to produce novel and valuable ideas ycomponents of creativity xexpertise ximaginative thinking skills xventuresome personality xintrinsic motivation xcreative environment

Genetic Influences zThe most genetically similar people have the most similar scores Similarity of intelligence scores (correlation) Identical twins reared together Identical twins reared apart Fraternal twins reared together Siblings reared together Unrelated individuals reared together

zHeritability ythe proportion of variation among individuals that we can attribute to genes yvariability depends on range of populations and environments studied Genetic Influences Similarity of intelligence scores (correlation) Adopted children and biological parents Adopted children and adoptive parents

Genetic Influences

Environmental Influences  The Schooling Effect Intelligence scores drop over the summer when students are not in school

Group Differences  Average IQ scores by racial groups  Whites: Roughly 100  Blacks: Roughly 85  Hispanics: Roughly 92/93  Differences are diminishing over time  What explains these differences?

Group Differences zGender Differences yGirls score higher on: xSpelling xVerbal Ability xNonverbal Memory xSensation (more sensitive) xDetecting Emotion yBoys outnumber girls in special education, talk later, stutter more often yGirls now match or surpass boys at math

The Question of Bias  Are intelligence tests biased?  Depends on definition of “biased,” but…  Yes, often due to CULTURAL BIAS  Chitling Test, Australian Aboriginie Test examples  Stereotype Threat  A self-confirming concern that one will be evaluated based on a negative stereotype  Example: Women score higher on math tests when no male test-takers are in the room

Group Differences  Stereotype Threat  A self-confirming concern that one will be evaluated based on a negative stereotype

Genetic Influences zGroup differences and environmental impact Variation within group Difference within group Poor soilFertile soil Seeds

Genetic Influences zThe Mental Rotation Test of Spatial Abilities Which two circles contains configuration of blocks identical to the one in the circle at left? StandardResponses